Fin device for missile

ABSTRACT

A stabilizing fin for a missile. One end of the fin is mounted in a hingelike fashion on a holder so that the fin can be folded in relation to the holder about a first axis parallel with the leading edge of the fin. The holder is mounted in a recess in the body of the missile and is rotatable about a second axis at right angles to the longitudinal extension of the missile. The first axis is so positioned in relation to the second axis that by rotation of the holder the first axis can be moved from a position within the recess to a position entirely outside the body of the missile and vice versa.

Unite States Patent [54] FIN DEVICE FOR MISSILE 7 Claims, 2 Drawing Figs.

[52] US. Cl 244/327 [51] Int. Cl r. F42b 15/16 [50] Field of Search 244/138,

Primary ExaminerRobert F. Stahl Altorney---Hane & Baxley ABSTRACT: A stabilizing fin for a missile. One end of the fin is mounted in a hingelike fashion on a holder so that the fin can be folded in relation to the holder about a first axis paral lel with the leading edge of the fin. The holder is mounted in a recess in the body of the missile and is rotatable about a second axis at right angles to the longitudinal extension of the missile. The first axis is so positioned in relation to the second axis that by rotation of the holder the first axis can be moved from a position within the recess to a position entirely outside the body of the missile and vice versa.

FIN DEVICE FOR MISSILE BACKGROUND OF THE INVENTION The invention relates to a fin device for missiles such as guided missiles, rockets and the like. Such a fin device consists of a plurality of fins mounted circumferentially on the body of the missile to provide aerodynamic stability in flight.

Such a fin device entails disadvantages in the storage and transport of the missile, since the fins protruding from the body of the missile increase the space requirements and render the handling more difi'tcult. The protruding fins may also cause difficulties in the case that the missile is to be launched through a launching tube.

To eliminate these disadvantages it has previously been proposed to make the fins foldable so that the fins can be folded towards the body of the missile and be retained in this position during storage and transport, whereas before or during the launching of the missile the fins are unfolded to the position they should assume during the flight of the missile. Thus, it is known to provide the body of the missile with recesses into which the fins can be wholly retracted so that no parts of them are outside the external surfaceof the missile body. This arrangement is however disadvantageous because the said recesses take up a considerable space and reduces the space available for the propellent and the warhead of the mis-- sile. These recesses which must have a length which is somewhat larger than the length of the fins, also unfavorably afi'ect the aerodynamic propenies of the missile during its flight.

OBJECT AND SUMMARY OF THE INVENTION The primary object of the invention is to provide a fin device in which the fins can be folded towards the body of the missile to reduce the space requirements during storage and transport and in which the fins can be easily unfolded to the effective position, the device being such that it occupies as little as possible of the space in the interior of the missile.

According to the invention there is provided for each fin a holder which is turnable about a first axis in relation to the body of the missile, and the fin is attached to the holder and turnable in relation to the holder about a second axis, and the body of the missile is provided with a recess for receiving an end portion of the fin, the holder being turnable about said first axis to a first position in which said second axis is outside the missile, and the holder and the fin attached thereto is so positioned in relation to the recess that said end portion of the fin can be moved into and out of the recess by turning the older about said first axis.

When the holder is in the said first position the fin can be turned about the second axis carried by the holder to a position in which the side faces of the fin are about parallel to a tangential plane of the body of the missile. While all parts of the fin in this position are outside the outer surface of the missile. all parts of the fin are adjacent to the outer surface, and the total space requirement for the missile will therefore be considerably less than in the case when the fin is in its working position. From the folded position the fin can be moved to its working position by turning the fin about the second axis until the side faces of the fin are in parallel with the sides of the recess and turning the holder about the first axis so that an end portion of the fin is moved down into the recess. Since this recess only needs to receive an end portion of the fin it has a moderate extension aNd occupies only a small portion of the interior space of the missile.

The shifting of the fin from folded position to the working position can be effected manually for instance immediately before the missile is to be launched. However, the device can easily be so designed that the shifting is efi'ected automatically for instance immediately after the launching of the missile. If the missile is launched by means of a launching tube the fins may be in folded position as long as the missile is still inside the tube but are unfolded as soon as the missile has left the tube. The fin device can be so designed that the shifiing is effected by the air resistance, but the fin and its holder may also be provided with for instance spring means which act upon the holder and the fin so that the fin is moved to the correct position in relation to the recess.

The recess and the fin are preferably designed so that the fin is securely retained in its working position, or the device may be provided with suitable catch means-to lock the fin in the operative position. Also, the device can be provided with means for retaining the fins in folded position.

DRAWING AND DETAILED DESCRIPTION In the following the invention will be described more in particular with reference to the accompanying drawing.

FIG. 1 is a side view, partly in section, of a fin device according to the invention.

FIG. 2 is a diagrammatic rear view of a missile provided with a fin device according to the invention.

In the drawing 1 designates the outer wall of a missile. The intended direction of movement of the missile is indicated by an arrow in the right-hand portion of FIG. 1. A number of fins 2 are attached to the missile and arranged with equal angular spacing circumferentially about the missile.

As will be seen in FIG. 1 each fin 2 is pivotally mounted in a holder 3 by means of a shaft 4 which extends substantially in parallel with the leading edge of the fin 2. The holder 3 is pivotally mounted on a shaft 5 in the front portion of a recess 6 in the cover of the missile. The recess 6 has a width which is somewhat larger than the thickness of the fin 2.

In FIG. I the fin 2 is shown in its operative or working position in relation to the missile, that is the position which the fin should take up during the flight of the missile. In this position an end portion 7 of the fin is retracted in the recess 6. A part 8 of the fin rests against a rear wall portion of the recess 6. The part 8 may be fonned as a shoulder which rests against a correspondingly formed stop surface in the rear wall of the recess The holder 3 can be turned about the shaft 5 to such position that the shaft 4 is entirely outside the body of the missile. In this position the fin 2 can be turned about shaft 4 to the position shown in FIG. 2. In this figure the dash-dot lines indicate a tube 9 in which the missile can be contained during storage and transport, and this tube may also serve as a launching tube for the missile. On the inside the tube 9 may be provided with guiding bars I0, upon which one side of the holders 5 are resting.

In the shown embodiment it is assumed that the free ends of the fins 2 are situated ahead of the recess 6 and the shaft 5 when the fins are in the position shown in FIG. 2. If the missile is launched while the fins 2 are still in the position shown in FIG. 2, the fins are therefore subjected to air resistance and inertial forces which strive to move the fins outwards and rearwards. If for instance the launching is efi'ected in the tube 9 (FIG. 2) these forces will cause the fins to be moved to the position shown in FIG. I as soon as the missile leaves the tube 9. The shifting of the fin from the position shown in FIG. 2 to that shown in FIG. 1 takes place through a combined turning about the shafts 5 and 4. In order that the end portion 7 of fin 2 shall be moved into the recess 6, the fin 2 must be rotated about shaft 4 until its sides are substantially in parallel with the lateral surfaces of the recess 6. When the holder 3 during its rotation aboutshaft 5 has arrived at such a position that continued rotation would cause a first part of the fin 2 to enter the recess 6, it may happen that the fin 2 is not yet in such position that its sides are substantially parallel with the lateral surfaces of the recess 6. In such case some point on the edge of the end portion 7, for instance the edge 11 in the shown embodiment, will be pressed against some of the side edges of the recess 6. In order that the continued rotation of the holder 3 and the fin 2 shall not be stopped thereby, that edge portion of the end portion 7 which is the first to come into contact with an edge of the recess 6 is so positioned that by this contact a turning moment will be exerted on the fin 2 about the shaft 4 so that the fin 2 during the continued rotation of the holder 3 is guided into the recess 6. v

The shifting of a fin 2 from the position shown in H6. 2 to that shown in-FIG. .1 may, however, also be effected by means of spring devices. A first spring device may be adapted to I rotate the holder 3 about the shaft .5, and a second spring device may be adapted to rotate the fin'Z about the shaft 4,. the spring devices being so designed that they strive to rotate the holder3 and the fin 2 to the position shown .inFlG. 1.

Means may be provided in'the recess 6 to retain the fin 2 in its operative position and to prevent the tin. 2 from bouncing when it reaches its operative position. Thus, a part of the recess 6 may have a decreasing cross'section. and the holder 3 end portion (7) of the fin (2) is provided with an edge ('11) coacting with a lateral edge of said recess (6).to guide the fin when said end portion (7 enters the recess (6) so'that the fin during a first part of the entering movement is turned about I 'said' second shaft (4) to such position that the side surfaces of I the fin are substantially parallel with the side surfaces of the recess. 3. A device as claimed in claim 1, characterized in that the I recessat least in part has a tapered section, and that the holder or the end portion 7 may have a correspondingly formed part, I

which when entering the recess is pressed into the tapered part of the recess and is. retained in this by'wedge action.

The embodiment described above and shown in-the drawing I is given by way of example only and can be modified in many I ways within the scope of the invention.

We claim: I. Fin device for a missile. comprising fins attached to the body of the missile, characterized in that for each fin (2) there is provided a holder (3) which is turnable about a first axis 5) in relation 'to the body of the missile, that the fin (2) is attached to the holder (3)'and turnable in relation to the holder (3) about a second axis (4); and that the body of the missile is provided with a recess (6 for receiving an end portion ('7) of the fin (2), the holder (3) being'turnable about said first axis or said end portion of the tin has a' correspondingly formed I part which whenentering the said recess is pressed into said tapered part of the recess and is retained therein by wedge action.

' 4. A device as claimed in claim 1, characterized in that the fin (.2) is so arranged in relation to the holder (3) that when the holder is in said firstposition the free end of the tin is positioned ahead of the recess (6) as seen in the intended direction of movement of the missile.

5. A device as claimed in claim 1 characterized in thatsaid recess (6) has its main extension in parallel with the longitw' dinal direction of the missile.

6 A device as claimed in claim 1, characterized in that said I I first axis (.5) is situated in the recess (6) and extends at right (5) to a first position, in which said second axis'M) is outside I the missile (FIG. 2 and the holder (3) and the fin (2) at- 'tached thereto being so positioned in relation to said recess (6) that'said end portion '(7-) of the fin canbe moved into and out of'the recess by turning the holder about said first axis (5).

2. A device as claimed in claim 1, characterized in that said angles to the side walls of the recess. I

I 7. A device as claimed in claim 1, characterizedin that it comprises a first spring device striving to turn the holder (3) about said first axis (5) to such position that said end portion (7) is positioned in said'recess, and a second springdevice' I which strives to turn the fin about said second axis (4) to such position that the side surfaces of the fin are in parallel with the sides surfaces of the 'recess'(6). 

1. Fin device for a missile, comprising fins attached to the body of the missile, characterized in that for each fin (2) there is provided a holder (3) which is turnable about a first axis (5) in relation to the body of the missile, that the fin (2) is attached to the holder (3) and turnable in relation to the holder (3) about a second axis (4), and that the body of the missile is provided with a recess (6) for receiving an end portion (7) of the fin (2), the holder (3) being turnable about said first axis (5) to a first position, in which said second axis (4) is outside the missile (FIG. 2), and the holder (3) and the fin (2) attached thereto being so positioned in relation to said recess (6) that said end portion (7) of the fin can be moved into and out of the recess by turning the holder about said first axis (5).
 2. A device as claimed in claim 1, characterized in that said end portion (7) of the fin (2) is provided with an edge (11) coacting with a lateral edge of said recess (6) to guide the fin when said end portion (7) enters the recess (6) so that the fin during a first part of the entering movement is turned about said second shaft (4) to such position that the side surfaces of the fin are substantially parallel with the side surfaces of the recess.
 3. A device as claimed in claim 1, characterized in that The recess at least in part has a tapered section, and that the holder or said end portion of the fin has a correspondingly formed part which when entering the said recess is pressed into said tapered part of the recess and is retained therein by wedge action.
 4. A device as claimed in claim 1, characterized in that the fin (2) is so arranged in relation to the holder (3) that when the holder is in said first position the free end of the fin is positioned ahead of the recess (6) as seen in the intended direction of movement of the missile.
 5. A device as claimed in claim 1, characterized in that said recess (6) has its main extension in parallel with the longitudinal direction of the missile.
 6. A device as claimed in claim 1, characterized in that said first axis (5) is situated in the recess (6) and extends at right angles to the side walls of the recess.
 7. A device as claimed in claim 1, characterized in that it comprises a first spring device striving to turn the holder (3) about said first axis (5) to such position that said end portion (7) is positioned in said recess, and a second spring device which strives to turn the fin about said second axis (4) to such position that the side surfaces of the fin are in parallel with the sides surfaces of the recess (6). 